The present invention relates to coatings that are able to evolve heat (exothermic coatings) and more particularly to exothermic coatings that utilize non-metallic particles for achieving remarkable heating characteristics.
The art has proposed "electrically conductive" coatings utilizing metallic particles for anti-static applications. Coatings based on non-metallic particles even appear in the literature. These coatings, however, typically only generate low amounts of heat and often break down the binder when asked to achieve moderate to high temperatures (say, in excess of around 100.degree. C.). Nevertheless, the art is replete in such exothermic coatings teachings.
Nishino (U.S. Pat. No. 4,714,569) proposes to react a monomer having COOH, HN, or OH groups with a co-monomer in the presence of a peroxide catalyst to form a graft copolymer on the surfaces of the graphite and carbon black. The addition of an azo catalyst completes the reaction. Finally, a curing agent is used to form a three-dimensional network structure (i.e., paint).
Nahass (U.S. Pat. No. 5,591,382) proposes paints for charge dissipation which paints include cylindrical graphite carbon fibrils and a polymeric binder.
Mahabandi (U.S. Pat. No. 5,575,954) proposes conventional metallic and carbon conductive fillers in a unique binder to make a conductive polymer matrix.
Wakita (U.S. Pat. No. 5,567,357) proposes silver-plated copper powder to make a conductive paint.
Kim (U.S. Pat. No. 5,556,576) proposes metal, metal-coated glass, ceramics, or conductive carbon to prepare conductive coatings.
Namura (U.S. Pat. No. 5,549,849) proposes a combination of graphite particles, metal particles, and carbon black to prepare conductive coatings.
Hari (U.S. Pat. No. 5,516,546) proposes amorphous or spherical graphite, carbon fiber, metal particles, or mixtures thereof, to prepare conductive coatings. Wakabayashi (U.S. Pat. No. 5,425,969) proposes a conductive primer for polypropylene that utilizes carbon black, graphite, silver, nickel, or copper.
Ota (U.S. Pat. No. 5,407,741) proposes to use spherical graphic particles or a diameter of less than 500 .mu.m to prepare an exothermic conductive coating.
Ota (U.S. Pat. No. 5,378,533) proposes metallic coated hollow glass spheres to prepare a conductive coating.
Li (U.S. Pat. No. 5,372,749) proposes a surface treatment for conductive copper powder.
Rowlette (U.S. Pat. No. 5,334,330) proposes to use a mixture of conductive metal oxide powder and non-conductive particles to prepare an anisotropically electrically conductive coating composition.
Shrier (U.S. Pat. No. 5,248,517) proposes to use metals, metal alloys, conductive carbides, conductive nitrides, conductive borides, and metal-coated glass spheres to prepare a nonlinear transient over-voltage protection coating.
Yokoyama (U.S. Pat. No. 5,242,511) proposes to a copper alloy powder for use in electromagnetic shielding and similar uses.
Mio (U.S. Pat. No. 4,857,384) proposes to use metal oxide powder in preparing an exothermic conducting paste.
Gindrup (U.S. Pat. No. 4,624,798) proposes to use metal-coated microparticles in preparing electrically conducting compositions.
Ellis (U.S. Pats. Nos. 3,923,697, 3,999,040, and 4,064,074) proposes a blend of graphite, manganese dioxide, and zinc oxide in preparing electrically conductive compositions.
Neumann (U.S. Pat. No. 3,912,668) proposes to use metallic carbide in preparing paints that have low electrical impedance orthogonal to the plane of the coating.
The present invention solves many of the problems encountered in the art in formulating non-metallic exothermic coatings.